Exhaust gas discharged from an internal combustion engine of, for example, an automobile contains toxic components such as hydrocarbons (THC), carbon monoxide (CO), and nitrogen oxides (NOx). Hitherto, three-way catalysts have been used for removing such toxic components for detoxifying the exhaust gas. There have been proposed three-way exhaust gas pulifying catalysts in which a noble metal (e.g., Pt, Pd, or Rh) is supported on a carrier made of alumina, a composite oxide, or a similar material (see, for example, Patent Documents 1 to 4).